Harmonic balancer

Pick yourself up a set of dial indicator extensions. This way you can put the indicator's tip directly on the lifter....because like RRR said above it's critical (if you want accuracy) to have the indicator rod parallel with the lifter and there's no way it's happening with a pushrod between them. It usually takes some fussin' to get the dial indicator set up just right, but careful attention to all those little details is the difference between a good and a not-so-good result.